The primary objective of this research proposal is to analyze how central visual pathways may be modified by visual deprivation. In particular, the effects of monocular lid suture upon the normal organization of geniculo-cortical pathways of several mammals will be studied. Such animals include tree shrews, normal cats and Siamese cats. These deprivation studies will utilize the autoradiographic and horseradish peroxidase tracing methods. In addition to the studies regarding the effects of visual deprivation upon the brain, several studies will focus upon defining the normal connectivity of central visual pathways in a wide variety of mammals. In particular, the connectivity of the superior colliculus, pretectum and lateral geniculate nucleus will be analyzed using primarily the autoradiographic and horseradish peroxidase method.